THE RELATIONS OF METABOLISM TO FOOD-SUPPLY. 131 
and only a part of the nitrogen appeared during the twenty-four 
hours following its ingestion, viz.: 
With: fibrin: .35.c0ees3 ay le one cuee es 49.2 per cent. 
With felatinie. .scccves vee leases gc 387.6 “ « 
With peptone.... 0.0.0.0... cece eee 67.6 “ 
With asparagin .................00. 1950 
Rosemann’s* results upon the rate of nitrogen excretion by 
man, likewise cited above, indicate a similar effect of the non- 
nitrogenous nutrients, the fluctuations due to the ingestion of mixed 
food being much less sharp than those found by other experi- 
menters with proteids alone. 
If we accept Rosemann’s view (p. 101), that the sudden increase 
in the nitrogen cleavage is due, in part at least, to a direct stimulus 
to the metabolic activity of the cells, arising from the presence in 
the fluids of the body of an increased percentage of proteids, we 
may perhaps suppose that the simultaneous resorption of non- 
nitrogenous matter renders this stimulus less and so reduces the 
maximum rate of nitrogen cleavage. This conjecture possibly 
receives some support also from the results of Krummacher,{ who, 
contrary to Adrian and Munk, finds that the division of the 
proteid ration into several meals not only renders the rate of nitro- 
gen excretion more uniform, but reduces somewhat the total amount 
excreted. Gebhardt { has also obtained similiar results. 
There is also the possibility, however, that the non-nitrogenous 
nutrients may modify the rate at which the proteids are resorbed, 
or perhaps, as has been suggested by various investigators, the 
extent to which the proteids are converted into amide-like bodies 
by the pancreatic juice or the extent of proteid putrefaction in the 
intestines. Suggestive in this regard is the fact found by Gruber § 
that common salt, which acts as a stimulant to thesecretion of hydro- 
chlorie acid by the stomach, and would thus tend to favor gastric 
as compared with intestinal digestion of the proteids, produces an 
effect on the nitrogen excretion similar to that of the non-nitroge- 
nous nutrients. 
*Arch. ges. Physiol., 65, 343. 
} Zeit. f. Biol., 35, 481. 
{ Arch. ges. Physiol., 65, 611. 
§ Zeit. f. Biol., 42, 425. 
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